On Wed, Oct 24, 2018 at 06:28:56AM -0400, Pierre Neidhardt wrote:
> ambrevar pushed a commit to branch master
> in repository guix.
> 
> commit b5bb0b500bf0bc14bbb5d554a75d4f46f1d74795
> Author: Pierre Neidhardt <mail@ambrevar.xyz>
> Date:   Wed Oct 24 12:07:04 2018 +0200
> 
>     gnu: Add go-github-com-urfave-cli.
>     
>     * gnu/packages/golang.scm (go-github-com-urfave-cli): New variable.

[...]

> +(define-public go-github-com-urfave-cli
> +  (let ((commit "934abfb2f102315b5794e15ebc7949e4ca253920")
> +        (revision "0"))
> +    (package
> +      (name "go-github-com-urfave-cli")
> +      (version (git-version "1.19.1" revision commit))

There was already a package with the same variable name,
'go-github-com-urfave-cli'.

We should either remove one of them, or choose a different variable name
for one of them.